1. Field of the Invention
The present invention relates to a ceramic rotor for a turbocharger, particularly of the kind including an all ceramic turbine wheel and a metal shaft soldered or brazed together.
2. Description of the Prior Art
A silver-copper-titanium (Ag-Cu-Ti) alloy, silver-copper-nickel-titanium (Ag-Cu-Ni-Ti) alloy, etc. are used as filler metals for brazing a metal shaft to a ceramic turbine wheel to constitute a rotor for a turbocharger, as is well known in the art. Such brazing is generally advantageous since it can be attained relatively easily, i.e., its brazing temperature is relatively low (800.degree.-900.degree. C.), and a brazed joint has a relatively large strength. However, in case of being applied to a part or element exposed to a high temperature, brazing will become disadvantageous due to a lack of the high-temperature strength and the resistance to oxidation since the eutectic point of silver-copper (Ag-Cu) is low (780.degree. C.) and furthermore copper is gradually oxidized.